Machine for printing on cups and the like

ABSTRACT

A printing cylinder, divided into several peripheral segments which are limitedly radially displaceable on a rotating first hub, coacts with an array of supporting arms radiating from a rotating second hub whose axis is generally parallel to that of the first hub, the orbits of the segments in an outwardly extended position intersecting with those of a set of revolving cups carried on individually rotatable mandrels on the supporting arms. The segments or the mandrels are additionally tiltable about pivotal axes lying in their plane of rotation in order to compensate not only for disparities in the wall thickness of different cups but also for nonuniform wall thickness of a single cup to be imprinted.

United States Patent Van Der Roer 51 Oct. 3, 1972 [54] MACHINE FOR PRINTING 0N CUPS AND THE LIKE [72] Inventor: Humphrey Alphons Victor Van Der Roer, 174 Olympiaplein, Amsterdam, Netherlands [22] Filed: June 22, 1970 [21] Appl. No.: 48,116

[30] Foreign Application Priority Data June 21, 1969 Switzerland ..9606/69 [52] US. Cl ..101/39, 101/376 [51] Int. Cl. ..B4lf 17/28 [58] Field of Search 101/38-40, 376

[56] References Cited UNITED STATES PATENTS 3,521,554 7/1970 Zurick ..101/40 3,496,863 2/1970 Cracho et al. ..101/40 3,261,281 7/1966 Hartmeister 101/40 X 3,548,745 12/1970 Sirret et al ..101/40 2,326,850 8/1943 Gladfelter et al ..l0l/40 FOREIGN PATENTS OR APPLICATIONS 1,558,652 l/l969 France ..l0l/40 973,197 9/1950 France ..l0l/40 613,023 11/1948 Great Britain ..l0l/39 Pn'mary Examiner-Robert E. Pulfrey Assistant Examiner-Clifford D. Crowder Attorney-Karl F. Ross 7] ABSTRACT A printing cylinder, divided into several peripheral segments which are limitedly radially displaceable on a rotating first hub, coacts with an array of supporting arms radiating from a rotating second hub whose axis is generally parallel to that of the first hub, the orbits of the segments in an outwardly extended position intersecting with those of a set of revolving cups carried on individually rotatable mandrels on the supporting arms. The segments or the mandrels are additionally tiltable about pivotal axes lying in their plane of rotation in order to compensate not only for disparities in the wall thickness of different cups but also for nonuniform wall thickness of a single cup to be imprinted.

10 Claims, 9 Drawing Figures PATENTED 3 SHEET 2 [IF 3 m N E N Am, FI/REY 4. 1/. mu nee Eaffi cm 6W PATENTED W3 SHEET 3 [If 3 MACHINE FOR PRINTING ON CUPS AND THE LIKE My present invention relates to a machine for imprinting, e. g. by the offset method, generally cylindrical workpieces such as cups of paper or plastic material.

Such cups, widely used in the food industry, are frequently imprinted with informative, decorative and/or advertising messages, often in two or more colors. For this purpose they-can be conventionally mounted on an array of rotatable mandrels moving past a printing cylinder.

For a sharp reproduction of the message characters and other symbols on the outer surface of the workpiece it is necessary, in these conventional systems, to minimize deviations of that surface from a figure of revolution centered on the axis of rotation of the mandrel; this requirement, however, is not-always met as wall thicknesses of, say, injection-molded cups are subject to variations not only as between different .cups but also over the circumference of a .single workpiece. Such imperfections, usually on'the orderof 0.1 to 0.5 mm, have been compensated heretofore by covering the printing cylinder with an elastic layer serving as a carrier for the printing matrix or matrices. The necessary deformability of these layers, however, impairs (the accuracy of reproduction so that fine details could be lost.

It is, therefore, the general object of mypresent invention to provide an improved printing machine of this type in which the aforestated disadvantages are avoided.

Owing to the accuracy with which the cylinder and the workpiece has heretofore to confront each other during the printing operation, conventional systems for the imprinting of cups and the like were provided with intermittent drive means so as to halt the movement of the cups or other articles past the cylinder (or vice versa) during printing, with the result that not more than 12,000 to 14,000 cups per hour could be printed in a typical machine of this nature. Another object of my invention, therefore, is to provide an improved cup printer enabling continuous movement of both the cylinder and the cups with consequent increase in output and a longer service life of the equipment owing'to reduced wear.

These objects are realized, pursuant to the present invention, by the provision of two sets of supports revolving about hubs with substantially parallel axes in limitedly intersecting orbits and with freedom of relative radial displacement against an outwardly directed biasing force, one set of supports carrying printing matrices while the other set of supports accommodates the workpieces with freedom of rotation about individual axes. In the zone of orbital intersection, either the support carrying the printing matrix or the one carrying the rotating workpiece yields sufficiently to let the matrix bear upon the confronting workpiece surface with the necessary contact pressure which remains substantially uniform throughout that zone. Naturally, it is also possible to bias both sets of supports, rather than just one set, into a radially extended position while permitting their inward retraction upon contact between the workpiece and the matrix.

Advantageously, pursuant to another feature of my invention, the two sets :of supports are also provided with a second degree of relative freedom to compensate for surface irregularities of a given workpiece, sucha nonuniform wall thickness of a single cup. To this end the supports of one set are mounted on an associated hub with freedom of movement about respective pivotal axes parallel to their plane of rotation, thus enabling the generatrices of the cylindrical or slightly conical cups to align themselves with those of the printing matrices regardless'of variations in wall thickness.

In a preferred embodiment, the matrix supports have the shape of cylinder segments secured-to respective mounting blocks which in turn are slidable on guide rods radiating from the hub. The outwardly acting biasing force may then be provided by air cylinders formed in these blocks, these cylinders being open toward the hub to receive pistons carried thereon whereby a volume of compressed air in each cylinder exerts an outward force on the block and the corresponding cylinder segment. Thelatter may be connected with the block through a swivel head affording the aforedescribed second degree of relative freedom.

In accordance with a further feature of my invention, stationary guide rails or the like alongside the orbit of the cylinder segments engage rollers or other coacting formations on the blocks and/or on the segments for the purpose of starting an inward retraction of each segment as it approaches the zone of intersection, thereby softening the impact between the segment and the next workpiece to be imprinted,.and/or for maintaining a predetermined attitude of the swivelable segment at locations remote from the zone of intersection to facilitate the transfer of ink to the segment from an associated printing roller.

The above and other features of my invention will be described in detail hereinafter with reference to the accompanying drawing in which:

FIG. la shows, inaxial section, a cup mounted on a mandrel for imprinting by a machine embodying my present improvement;

FIGS. lb and 1c are views similar to FIG. la showing cups of somewhat irregular shape;

FIG. 2 is a side-elevational view of a printing cylinder forming part of my improved machine;

FIG. 3 is a sectional view of the printing cylinder taken on the line III III of FIG. 2;

FIG. 4 is a diagrammaticside-elevational view of the printing cylinder of FIGS. 2 and 3 together with an array of cup-supporting mandrels cooperating therewith;

FIG. 5 is a top view of the assembly of FIG. 4;

FIG. 6 is a fragmentary view similar to FIG. 4, illustrating a modification; and

FIG. 7 is a'fragmentary view similar to FIG. 5, relating to the embodiment of FIG. 6.

In FIG. la there is shown, diagrammatically, a mandrel 22 mounted on a hollow spindle 41 for rotation about an axis 31. A cup 50a of plastic material is supported on the mandrel .11 and is firmly held thereon by suction exerted through the hollow spindle 31 as indicated by an arrow 42; to release the cup from the mandrel, this suction is relieved or replaced by air pressure directed toward the bottom of the cup.

FIG. lb shows a similar cup 50b which, however, is heavier at the left than at the right. Another cup 50c shown in FIG. 1c is also irregular in shape by having a peripheral wall tapering downwardly on the left and upwardly on the right. The divergence in wall thickness has been exaggerated in FIGS. 1b and 10 for the sake of clarity.

With conventional cup printers as discussed above, workpieces such as those shown in FIGS. lb and 16 could not be properly imprinted and would usually be classified as rejects. In my improved system described hereinafter, these workpieces can be handled in the same manner as the cup 500 in FIG. 1a.

FIGS. 2 and 3 show a cylinder designed for offset printing, comprising four peripheral segments I mounted on respective blocks 2 which are slidably supported by rods 8 radiating from a central hub 5. Each block 2 is guided for radial movement by a pair of these rods 8 which are received in parallel bores 35 of the block.

Segments 1, whose outer peripheral surfaces carry printing matrices not shown, are pivotally connected with their blocks 2 through pins 3 and swivel heads 36 which form integral extensions of these blocks. The pivotal axes 32 of the segments 1, defined by their pins 3, lie within the plane of rotation of the segments which have bearings 4 engaged by the reduced tips 3 of the pins. It will be noted that these axes 32 are radially offset from the central axis of hub 5 so as to be approximately tangent to the orbit of the segments 1. Retaining bolts 14 are screwed into the hub 5 and have heads bearing upon a shoulder 37 of each block 2 for limiting the outward displacement thereof.

Hub 5 has a shaft 7 driven by a motor 38, an extension 6 of this shaft being formed with a central bore 13 communicating via transverse channels 12 with several air cylinders 9, open toward hub 5, by way of tubular stems of respective pistons received in these cylinders. Air under pressure, from a source symbolized by an arrow 45, is thus fed to these air cylinders to maintain therein an elastic gas cushion acting upon the pistons 10 to bias the blocks 2 radially outwardly with reference to the hub. Each block 2 and each segment 1 is provided with a respective guide roller 15 and 16 en gageable with associated tracks 23, 23' and 24 (FIG. 4) in certain angular positions thereof.

As further illustrated in FIGS. 4 and 5, segments 1 revolve in an orbit O, centered on the axis of shaft 7, which intersects between points D and D with an orbit 0 of a set of mandrels 22 which are rotatably supported, with the aid of hollow spindles 41 as described in connection with FIG. 10, on a set of arms 43 radiating from a hub 44 whose shaft 21 is driven from a motor 40. Arms 43 also form conduits for the application of suction or pressure to the spindles 41 as described above. Motors 38 and 40 continuously drive the segmental matrix support 1 and the cup support 22 in the same direction, here clockwise, as indicated by arrows A and B.

Arrayed about the periphery of the printing cylinder 1, 2, at locations remote from the zone of intersection of orbits 0' and 0", are several inking rollers a, 20b, 20c and 20d. If the four segments 1 are designed to carry complementary matrices or cuts of different color, these rollers are selectively moved into contact with the respective segments to coat them with suitably colored ink. It will be noted that the track 24, engaging the guide rollers 16 of the segments 1, maintains these segments in the proper attitude and position for engagement with the inking rollers over their entire axial length. On the other hand, curved rail 23 and the cooperating track segment 23 impart an inward thrust to a roller 15 of a block 2 whose segment 1 approaches the point of intersection D so as to deflect that segment from its orbit to cushion the shock of its engagement with an oncoming mandrel 22 carrying a cup to be imprinted. This cup and its mandrel are then entrained for counterclockwise rotation (arrow C) as viewed in FIG. 4. It will be apparent that the relative orbital speeds V and V of segments 1 and mandrels 22 should be such that the printing cylinder performs a full revolution and the cup rotates four times about its axis as they pass in mutual contact through the region between points D and D if, as assumed above-each of the four segments is to print a different color on the cup. This could also be achieved, though less conveniently, with the hubs 5 and 44 rotating in opposite directions.

In FIGS. 6 and 7 I have shown the four segments 30 of a similar printing cylinder whose shaft 107, however, is inclined at a small angle to the shaft 121 of a disk 34 serving as a support for the mandrels 22. In this embodiment the spindles (41 in FIG. 1a) carrying the mandrels 22 are replaced by the extremities of gooseneck-shaped rocker arms 39 which are journaled in sleeves 33, integral with disk 34, for rotation about pivotal axes 132 lying again parallel to or in the plane of rotation of the mandrels. It will be noted that axes 132, like the swing axes 32 of the segments 1 in the preceding embodiment, substantially bisect the height of the mandrels whereby an article similar to cups 500 (FIG. 1c) can pivot in one sense or the other to compensate for its divergent wall thickness as described above. Stops, not shown, limit the swing of the mandrels 22 in the system of FIGS. 6 and 7 and of segments 1 in that of FIGS. 2 5. As will be apparent from FIG. 6, axes 132 are remote from the central axis of rotation and are substantially tangent to the orbit of the mandrels 22.

The printing cylinder of FIGS. 6 and 7 may be provided with the aforedescribed guiding system 15, 23, 23'; rollers 16 and tracks 24 will be omitted, however, since the segments 30 are not pivotable.

With a system as disclosed above, plastic and paper cups can be imprinted at a rate greatly exceeding the number of 12,000 to 14,000 per hour realizable with conventional cup printers.

Naturally, the outward biasing of segments 1 or 30 could also be accomplished with the aid of springs supplementing or replacing the air cushions 9 of FIG. 2.

lclaim:

l. A printer for generally cylindrical workpieces, comprising a first hub rotatable in a plane about a first central axis; a set of first supports substantially in the shape of cylinder segments arranged in a circle centered on said first axis and adapted to carry respective printing matrices; a second hub rotatable in a plane about a second central axis generally parallel to said first axis; a set of second supports arranged in a circle centered on said second axis for holding said workpieces with freedom of rotation about individual axes; first mounting means connecting said first supports with said first hub; second mounting means connecting said second supports with said second hub; and drive means for rotating said hubs with the orbit of said matrices limitedly intersecting the orbit of said workpieces; at least one of said mounting means including biasing means for urging the associated supports radially outwardly into an extended position defining the corresponding orbit while enabling inward yielding of said associated supports upon contact between said workpieces and said matrices along the zone of intersection of their orbits; the supports of at least one set being secured to their hub by the associated mounting means with freedom of pivotal motion about respective swing axes which pass through the last-mentioned sup ports in a direction parallel to their plane of rotation.

2. A printer as defined in claim 1 wherein said second supports include a peripheral array of sleeves centered on said swing axes and rocker arms in said sleeves swingable about said pivotal axes, said rocker arms terminating in mandrels rotatable about axes transverse to said swing axes.

3. A printer as defined in claim 1 wherein said work pieces are cup-shaped, said second supports including mandrels fitting inside said workpieces and suction means on said mandrels for releasably retaining said workpieces thereon.

4. A printer as defined in claim 1 wherein said hubs are provided with continuously operative drive means for rotating same.

5. A printer as defined in claim 1 wherein said first mounting means comprises a set of guide rods radiating from said first hub and a set of blocks slidably engaging said guide rods, said biasing means bearing upon said blocks.

6. A printer for generally cylindrical workpieces, comprising a first hub rotatable in a plane about a first axis; a set of first supports substantially in the shape of cylinder segments centered on said first axis and adapted to carry respective printing matrices; a second hub rotatable in a plane about a second axis generally parallel to said first axis; a set of second supports centered on said second axis for holding said workpieces with freedom of rotation about individual axes; first mounting means connecting said first supports with said first hub, said first mounting means including a set of guide rods radiating from said first hub and a set of blocks slidably engaging said guide rods; second mounting means connecting said second supports with said second hub; drive means for rotating said hubs with the orbit of said matrices limitedly intersecting the orbit of said workpieces; and biasing means bearing upon said blocks for urging said segments radially outwardly into an extended position defining the orbit of said matrices while enabling inward yielding of said segments upon contact between said workpieces and said matrices along the zone of intersection of their orbits, said biasing means including a set of air cylinders on said blocks open toward said first hub and a set of pistons on said first hub received in said air cylinders.

7. A printer as defined in claim 6 wherein the supports of at least one set are secured to their hub by the associated mounting means with freedom of pivotal motion about a swing axis parallel to their plane of rotation.

8. A printer as defined in claim 6, further comprising stationary deflectin means alongside the orbit of said segments and coac mg formations on said blocks for imparting an initial inward motion to said segments upon the approach of said zone of intersection.

9. A printer for generally cylindrical workpieces, comprising a first hub rotatable in a plane about a. first axis; a set of first supports substantially in the shape of cylinder segments centered on said first axis and adapted to carry respective printing matrices; a second hub rotatable in a plane about a second axis generally parallel to said first axis; a set of second supports centered on said second axis for holding said workpieces with freedom of rotation about individual axes; first mounting means connecting said first supports with said first hub, said first mounting means including a set of guide rods radiating from said first hub, a set of blocks slidably engaging said guide rods, and a set of swivel heads on said blocks defining pivotal axes parallel to their plane of rotation, said segments being fulcrumed on said swivel heads; second mounting means connecting said second supports with said second hub; drive means for rotating said hubs with the orbit of said matrices limitedly intersecting the orbit of said workpieces; and biasing means bearing upon said blocks for urging said segments radially outwardly into an extended position defining the orbit of said matrices while enabling inward yielding of said segments upon contact between said workpieces and said matrices along the zone of intersection of their orbits.

10. A printer as defined in claim 9, further comprising stationary guide means alongside the orbit of said segments and coacting formations on said segments for maintaining the latter in a predetermined attitude at a location remote from said zone of intersection, and inking means engageable with said segments at said remote location. 

1. A printer for generally cylindrical workpieces, comprising a first hub rotatable in a plane about a first central axis; a set of first supports substantially in the shape of cylinder segments arranged in a circle centered on said first axis and adapted to carry respective printing matrices; a second hub rotatable in a plane about a second central axis generally parallel to said first axis; a set of second supports arranged in a circle centered on said second axis for holding said workpieces with freedom of rotation about individual axes; first mounting means connecting said first supports with said first hub; second mounting means connecting said second supports with said second hub; and drive means for rotating said hubs with the orbit of said matrices limitedly intersecting the orbit of said workpieces; at least one of said mounting means including biasing means for urging the associated supports radially outwardly into an extended position defining the corresponding orbit while enabling inward yielding of said associated supports upon contact between said workpieces and said matrices along the zone of intersection of their orbits; the supports of at least one set being secured to their hub by the associated mounting means with freedom of pivotal motion about respective swing axes which pass through the last-mentioned supports in a direction parallel to their plane of rotation.
 2. A printer as defined in claim 1 wherein said second supports include a peripheral array of sleeves centered on said swing axes and rocker arms in said sleeves swingable about said pivotal axes, said rocker arms terminating in mandrels rotatable about axes transverse to said swing axes.
 3. A printer as defined in claim 1 wherein said workpieces are cup-shaped, said second supports including manDrels fitting inside said workpieces and suction means on said mandrels for releasably retaining said workpieces thereon.
 4. A printer as defined in claim 1 wherein said hubs are provided with continuously operative drive means for rotating same.
 5. A printer as defined in claim 1 wherein said first mounting means comprises a set of guide rods radiating from said first hub and a set of blocks slidably engaging said guide rods, said biasing means bearing upon said blocks.
 6. A printer for generally cylindrical workpieces, comprising a first hub rotatable in a plane about a first axis; a set of first supports substantially in the shape of cylinder segments centered on said first axis and adapted to carry respective printing matrices; a second hub rotatable in a plane about a second axis generally parallel to said first axis; a set of second supports centered on said second axis for holding said workpieces with freedom of rotation about individual axes; first mounting means connecting said first supports with said first hub, said first mounting means including a set of guide rods radiating from said first hub and a set of blocks slidably engaging said guide rods; second mounting means connecting said second supports with said second hub; drive means for rotating said hubs with the orbit of said matrices limitedly intersecting the orbit of said workpieces; and biasing means bearing upon said blocks for urging said segments radially outwardly into an extended position defining the orbit of said matrices while enabling inward yielding of said segments upon contact between said workpieces and said matrices along the zone of intersection of their orbits, said biasing means including a set of air cylinders on said blocks open toward said first hub and a set of pistons on said first hub received in said air cylinders.
 7. A printer as defined in claim 6 wherein the supports of at least one set are secured to their hub by the associated mounting means with freedom of pivotal motion about a swing axis parallel to their plane of rotation.
 8. A printer as defined in claim 6, further comprising stationary deflecting means alongside the orbit of said segments and coacting formations on said blocks for imparting an initial inward motion to said segments upon the approach of said zone of intersection.
 9. A printer for generally cylindrical workpieces, comprising a first hub rotatable in a plane about a first axis; a set of first supports substantially in the shape of cylinder segments centered on said first axis and adapted to carry respective printing matrices; a second hub rotatable in a plane about a second axis generally parallel to said first axis; a set of second supports centered on said second axis for holding said workpieces with freedom of rotation about individual axes; first mounting means connecting said first supports with said first hub, said first mounting means including a set of guide rods radiating from said first hub, a set of blocks slidably engaging said guide rods, and a set of swivel heads on said blocks defining pivotal axes parallel to their plane of rotation, said segments being fulcrumed on said swivel heads; second mounting means connecting said second supports with said second hub; drive means for rotating said hubs with the orbit of said matrices limitedly intersecting the orbit of said workpieces; and biasing means bearing upon said blocks for urging said segments radially outwardly into an extended position defining the orbit of said matrices while enabling inward yielding of said segments upon contact between said workpieces and said matrices along the zone of intersection of their orbits.
 10. A printer as defined in claim 9, further comprising stationary guide means alongside the orbit of said segments and coacting formations on said segments for maintaining the latter in a predetermined attitude at a location remote from said zone of intersection, and inking means engageable with said segments at said remote location. 